Methods and apparatus for large diameter wafer handling

ABSTRACT

A front semiconductor opening wafer container for large diameter wafers includes a container portion and a door. The container portion includes a left closed side, a right closed side, a closed back, an open front, and an open interior including a plurality of slots for receiving and containing the wafers. The door is attachable to the container portion to close the open front and selectively latchable to the container portion. Optimized sag control is provided as well as enhanced structural rigidity, and wafer seating features.

RELATED APPLICATIONS

The present application is a continuation application of U.S.application Ser. No. 13/847,345, filed Mar. 19, 2013, which is acontinuation application of U.S. application Ser. No. 12/812,729 filedSep. 24, 2010, now abandoned, which is a National Stage Application ofPCT/US2009/030870, filed Jan. 13, 2009, which claims the benefit of U.S.Provisional Application Nos. 61/020,736, filed Jan. 13, 2008, and61/134,604, filed Jul. 11, 2008, all of the above applications are fullyincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to semiconductor processing equipment. Morespecifically it relates to carriers for transporting and storingsemiconductor wafers.

BACKGROUND OF THE INVENTION

As the number of circuits per unit area has increased, particulates havebecome more of an issue for semiconductor wafers. The size ofparticulates that can destroy a circuit has decreased and is approachingthe molecular level. Particulate control is necessary during all phasesof manufacturing, processing, transporting, and storage of semiconductorwafers. Particle generation during insertion and removal of wafers intocarriers and from movement of wafers in carriers during transport needsto be minimized or avoided.

Driven by economies of scale, the size of wafers utilized insemiconductor fabrication facilities (fabs) has continually increased.Currently there are a number of fabs that process 300 mm wafers. It isanticipated that soon the maximum size of commercially processed waferswill increase to 450 mm. With the significant leaps in the size ofprocessed wafers, new issues and problems arise that were not presentwith smaller sized wafers.

For example, although wafer containers are often robotically handledsuch as by gripping robotic flanges on the top of the containers, theyare still manually handled in many instances and typically come equippedwith or have optional side handles. It is still relatively easy forpersonnel, by using such handles, to manually transport standardized 300mm containers loaded with wafers as such containers often around weigh20 pounds.

Standards for 450 mm wafers, such as the number of wafers in containersand the spacing between wafers, may very well remain the same as current300 mm wafer container standards due to existing equipmentcompatibilities and cost pressures. And, of course, as wafers get largerin diameter, they correspondingly get heavier. A wafer container thatholds the same number of 450 mm wafers as is provided in standardized300 mm containers is expected to weigh approximately 40 pounds. At thisweight, manual handling starts to become more difficult.

Using comparable thicknesses of polymer walls for a larger container maynot provide sufficient structural rigidity of the container. That is,the container would be expected to be less dimensionally stable underloading, transfer and shipping due to the greater dimensions and greaterexpanses of polymer. Thickening the walls and adding significantstrengthening structure would further increase the weight of 450 mmwafer containers.

Moreover, conventional 300 mm wafer containers are typically injectionmolded. It is anticipated that it will be difficult to adequatelycontrol the dimensions of larger containers utilizing comparableinjection molding practices and comparable or larger wall thicknesses.Currently 300 mm wafer containers generally utilize the shell as theprincipal structural member for positioning components that interfacewith wafers and outside equipment, namely the wafer supports and thekinematic coupling machine interface.

In addition, the open interior volume will significantly increase aswill the area of the open front that sealingly receives the door. Thissuggests more difficult sealing issues between the door and thecontainer portion.

Wafers of larger dimensions will also have significantly greater sagwhich will make them more susceptible to damage during handling andtransport and require unique support not required for smaller wafers.This greater sag presents challenges in maintaining the desired spacingbetween wafers while still allowing placement and removal of the wafersrobotically by robotic arms and that are known as end effectors. Suchdevices are inserted between wafers in the front opening containersgenerally underneath a wafer to be grasped and removed. It is criticalthat there is no contact with the end effector with either adjacentwafer or the wafer container during insertion of the end effector tograsp the wafer. Once the wafer is grasped, removal must be accomplishedwithout scraping or any contact by the end effector or wafer beingremoved with the adjacent wafers or container. Increased sagging of 450mm wafers compared to 300 mm wafers make such retrieval and placementoperations substantially more difficult in the 450 containers comparedto 300 mm containers. Similarly, during placement of a wafer in a wafercontainer, no contact with adjacent wafers or the container ispermissible. Current industry standards discussions and proposedstandards by SEMI (Semiconductors Equipment and Materials International,a trade association) have tentatively allowed 68 degrees at the centerrear of the wafer that is available for grasping (with at the verycenter rear for a wafer cushion feature) the 450 mm wafers. Suchdiscussions and proposed standards also provide 72 degrees at the frontcenter of the wafer for grasping or engagement by an end effector.Conventional front opening wafer containers provide front center, atleast about 120 degrees of an access opening which may provide excessivefront sag of the wafers making end effector insertion and engagementproblematic.

Thus, it would be desirable to develop front opening configurations for450 mm wafer containers that have design attributes for minimizing wafersag and minimizing weight of the container. In addition, configurationsproviding improved sealing characteristics for the doors would bedesirable. Moreover, configurations providing enhanced wafer support toaccommodate storing of 450 mm wafers in wafer containers as well duringrobotic handling of the wafers would be desirable. Providing a containerthat minimizes the damage that could be caused to wafers by warpage orshrinkage of the shell components would also be desirable.

SUMMARY OF THE INVENTION

A wafer container or microenvironment for transporting or holding wafersin a horizontal axially aligned arrangement can have a container portionwith an open front and a closeable door. The container is particularlyamenable for transport of wafers greater than 300 mm, for example 450 mmwafers, but aspects herein may be suitable for incorporation into 300 mmwafer containers and containers for other sizes of wafers and othersubstrates.

This invention, aspects of the invention, and the embodiments describedherein are applicable to and include wafer containers intended to beutilized exclusively in fabs where the wafers therein are always nearlyhorizontal (known as FOUPS in the context of 300 mm wafer containers) aswell as wafer containers that are loaded and unloaded with the wafers ina horizontal orientation and where the containers are then rotated 90degrees such that the wafers are vertical for shipping or transport.Such wafer containers utilized for shipping wafers among differentfacilities are generally known as FOSBS (Front Opening Shipping Boxes)in the context of 300 mm wafer containers.

In one embodiment, the container portion comprises a framework and shellportion. The framework comprises functional interface componentsincluding a rigid kinematic coupling plate, rigid wafer supports, and arigid door frame interconnected together. The shell, which may compriseone or more pieces, is attached thereto. In particular embodiments,portions of the framework may be a metal, for example aluminum thatprovides enhanced structural rigidity over conventional polymers.Additionally, high strength polymers may be utilized for the frameworkportions such as polyetheretherketone (PEEK), or composite pieces may beutilized comprising metals and polymers or different polymers.

The shell is preferably formed of a transparent polymer permittingviewing of the wafers therein. The shell may be formed of conventionalpolycarbonate or other polymers and may be conventionally injectionmolded. In certain embodiments highly suitable for the larger containersfor 450 mm wafers, the shell may be vacuum formed. Moreover, with vacuumforming, multiple layers of compatible polymers may be utilized. Theshell may be formed of separate pieces, such as two clam shell piecesassembled together, or may be formed of a single vacuum moldedcomponent.

In particular embodiments, the shell is independent of criticaldimensional, structural, and/or functional interface requirements. Forexample, in particular embodiments, the shell is not relied upon forpositioning interface features such as the kinematic coupling, the doorframe, and the wafer supports. Rather, these features or components areconnected to one another and the shell is attached to the interconnectedfunctional componentry. The shell may be attached at the door frame andthe bottom of the container at the kinematic coupling plate, but eithernot be connected to the wafer supports or only connected to the wafersupports at the bottom of the container. This provides independence ofthe functional interface features from molding variations while notaffecting the performance or relative placement of the criticalcomponents, particularly the functional interface features of the wafercontainer.

In particular embodiments of the invention, the shell includes anintegral horizontal projection that projects outwardly with respect tothe exterior. The projection can be configured as a band extendingaround the shell on three sides, for example, the left side, the rightside, and the back side. The projection may also define a recess in theinterior of the shell. The projection may be formed by a portion of thewall projecting outwardly with the wall thickness remaining nominallythe same. The band may be continuous on all three sides or may bepositioned on the left side and right side and not extend around orentirely around the back side. The band provides an integral handlingfeature that provides substantial structural strength enhancement to theshell with minimal weight expense. Where the shell is formed from vacuummolding, the interface between two clam shell pieces may suitably be atthe outwardly projecting band.

In particular embodiments, the wafers are supported by wafer supportsthat are part of the framework. The wafer supports may be attached tothe shell at the bottom of the container but not thereabove, or may notbe attached to the shell at all, instead attaching only to the internalframework of the container.

The door comprises a latch mechanism which is conventionally keyoperated and seals to the door frame. In particular embodiments, theinterface between the door and the container portion, at the door frame,provides a interlaced connection. The door frame has a slot or grooveinwardly directed and the door has a projection that enters the slotwhereby said projection is constrained within the slot. The door framehas an upper horizontal portion and a lower horizontal portion where theslot or slots extend horizontally and the corresponding projection orprojections on the door also extend horizontally and, when engaged insaid slot, the door by way of the projection is constrained upwardly anddownwardly. Similarly, the door frame may have a left vertical portionand a right vertical portion where the slot or slots extend verticallyand the corresponding projection or projections on the door also extendvertically and, when engaged in said slot or slots, the door by way ofthe projection or projections is constrained to the left and to theright. The slot may be continuous or not continuous around the doorframe and similarly the door may have a single cooperating projectionextending around the entire periphery of the door or more than oneprojection at selected portions of the periphery of the door. Inparticular embodiments, the slot or groove will have an elastomeric sealseated therein. In other embodiments, a seal may be positioned out ofthe slot or groove or on the door. Generally, the seal will extendaround the entirety of the door frame defining the door opening andengage with the entirety of the door periphery. The seal may also extendaround the entirety of the door periphery and engage with the entiretyof the door frame defining the door opening.

The door frame may be formed of a plurality of components. Particularly,the door frame may be configured as two layers or components thatsandwich the shell therebetween. This is a particularly suitableconfiguration for vacuum molded shell portions. Seal material may beutilized at such a junction to facilitate complete sealing of themicroenvironment. The door frame can be formed of rigid materials, suchas aluminum or the like, rigid polymers or a composite configuration.

In an embodiment of the invention, rigid frame members can support thepolymer wafer shelves and connect the wafer shelves to a rigid kinematiccoupling plate.

In an embodiment of the invention the shell portion is comprised of oneor more vacuum molded shell pieces assembled with the kinematic couplingplate and internal framework.

A feature and advantage is that the weight of the container portion maybe minimized by utilizing thinner shell portions than in conventionalwafer containers.

In a certain embodiment, the shell provides primarily a containmentfunction while relying on internal framework for rigidly securing thewafer supports with respect to the kinematic coupling and the front doorframe on the bottom of the carrier. A feature and advantage is thatdeflection, movement, or expansion of the shell does not directly moveor involve the wafers and the wafer seating positions are isolated fromthe portions of the shell that are deflectable, movable, or expandable.A further advantage and feature of the invention is that the compositeconstruction and isolation of the shell from the functional interfaceportions minimizes the negative effects associated with molding largecarriers such as warpage and shrinkage.

In particular embodiments, a manual handle can be provided that is not aseparate component from the shell. A feature and advantage of such aconfiguration is that the manual handle provides enhanced structuralstrength of the shell compared to a featureless shell wall. The manualhandle may be comprised of two substantially horizontal wall portions, atop wall portion and a bottom wall portion, and a vertical wall portionconnecting and integral to the substantially horizontal wall portions.The horizontal wall portions can be vertically separated by a distancesized to allow simultaneous hand gripping of the top and bottomhorizontal wall portions, with a user's left hand grasping the manualhandle at the left side of the container and the user's right handgrasping the manual handle at the right side of the container.

Further aspects of the invention particularly suitable for 300 mm wafersand larger include enhanced wafer support features. In particularembodiments, one or more stacks of thin (in the vertical direction)cantilevered projections extend from the back of the cassette forwardlytoward the open front (or door) of the container to provide undersidewafer support in positions spaced from the peripheral edge of the wafersto prevent or reduce sagging. The cantilever supports define a pluralityof slots vertically stacked for receiving, supporting, and dischargingwafers. In certain embodiments, the positioning of the forwardlyextending cantilever support extends in at least 50 mm from the edge, inother embodiments at least 75 mm from the peripheral edge of the wafers,and in other embodiments at least 100 mm inside the peripheral edge, inother embodiments, at least 125 mm inside the peripheral edge. Incertain embodiments, each slot has a first seating position where thewafers rest on the cantilever projections and a second seating positionelevated above the cantilever projections.

In particular embodiments, a wafer container can include one or morevertical stacks of generally rigid rearwardly positioned waferrestraints with horizontal V-shaped grooves. The surfaces defining theV-shaped grooves provide an upward lift to the wafers when they areurged backward into the slot, such as by insertion of the door intoengagement with the door frame whereby the front exposed edges of thewafers are engaged by a wafer restraint on the door. The front waferrestraint may have a V-shaped groove that further urges the wafer toelevate as the wafer edge rides up the lower inclined leg of thehorizontal V (open horizontally) during engagement of the door with thedoor frame. The second seating position is defined by the internal apexof the V-shaped grooves and is positioned above the first seatingposition.

In some embodiments, the angle of the V of the V-shaped engagementportions can vary depending on the positional placement of the V-shapedportions around the periphery of the wafer. Raising the wafer from ashelf seating position to the second position where the door is in placeand latched occurs by the wafers moving in the z direction with respectto the V-shaped seating portions. Considering the larger 450 mm wafers,it is advantageous to have several V-shaped seating portions that thewafer can ride up to reach the apex of the Vs, the seating position.Where the V-shaped seating portion is directly facing the insertiondirection of the wafer, the z direction, the lower leg incline can havea gradual slope and the angle between the upper leg (downwardly facing)surface and the lower leg (upwardly facing surface) is at a minimum.Where V-shaped seating positions engage the wafer at a position wherethe seating portion is facing more towards the x axis, that is, moretowards the sides of the container than the back of the container, theslope of the lower leg will be less and the angle defined by the lowerleg and the upper leg will be greater. The component of movementperpendicular to the V-shaped wafer portion is much less towards thesides of the wafer container than at the back of the wafer container,thus the greater angle V on the wafer engagement portions towards thesides compared to the back side allows continual support at differentperipheral locations on the wafer edge as the wafer is being elevated bythe insertion of the door. This minimizes sag in the wafer. The V-shapedengagement portions may be isolated discrete portions extending a fewmillimeters horizontally to engage the wafer, 5 to 20 mm in length orcan be much longer or even continuous on the backside of each slot. Incertain embodiments the lower leg of the engagement portions can have acurvature and similarly the curvature of the lower legs of the waferengagement portions positioned nearer the sides will be steeper than thecurvature of engagement portion nearer the back side. Note theutilization of V-shaped engagement portions in elevating the wafer asthe door is closed is disclosed in U.S. Pat. No. 6,267,245, which isincorporated by reference herein,

In particular embodiments, the lower leg of the V-shaped groove may belonger than the upper leg. This provides a larger engagement region forlarger wafers that may be sagging. This V-shaped groove is suitable forplacement on the inside backside of the container and also for placementat the front wafer restraint. The length of lower leg of the V-shapedgroove can be varied depending on the position of the V-shaped groovewith respect to a wafer seated in the container. Such can accommodatesag during loading of the wafer and during the elevating of the waferfrom a seating position without the door in place to a transport or doorseated position. A downwardly extending upside down ledge may connecteach lower leg upwardly extending surface to the adjacent upper legdownwardly extending surface.

In particular embodiments, the V-shaped grooves on the front waferrestraints that are attached to the inside of the door, can include afirst attached or base portion generally non-movably secured to thedoor, a deflectable wafer engagement portion or enlarged pad that is thefirst portion to contact the wafer when the door is applied to thecontainer, and an intermediate portion extending from the base portionto the deflectable wafer engagement portion. The horizontal V maypreferably extend the entirely of length of the wafer restraint and hasan aperture at the apex of the V-shaped groove on the intermediateportion defining fingers. Lower leg of the V-shaped groove in waferengagement portion can extend farther than the lower leg of the V-shapedportion at the intermediate portion or at the base portion. In an aspectof the invention the wafer restraint has a base portion an intermediatedual finger portion and a wafer engagement pad portion and wherein thewafer engagement pad portion swoops or is angled downwardly therebyproviding an enhanced engagement surface for the wafer edge of saggingwafers. The dual fingers at the intermediate portion provide torsionalstiffness while allowing flexibility in the z direction compared to asingle finger with the same flexibility. In a preferred embodiment thelower leg of the expanded pad will first contact the wafer edge as thedoor is being closed and the wafer engagement point will ride up the padand into the apex of the V-shape substantially the length of the waferrestraint.

In certain embodiments, the wafer shelves are formed by a stack ofindividual shelf sections that are identical with adjacent shelves. Thetop of the piece may be a mirror image of the bottom allowing the samemold of a single shelf piece to make the entirety of the shelves on theleft side and the shelves on the right side. A series of apertures mayallow for rods to extend through the stacked shelf pieces for alignmentand structural stability as well as attachment to the structuralframework.

In preferred embodiments each shelf has a forward most portion thatfollows the periphery of the wafer and extends inwardly from thelaterally outermost edge of the wafer when seated a distance in therange of 50 to 60 mm. In another embodiment, it can extend 55 to 65 mmand in another embodiment, 52 to 56 mm. In certain embodiments where thewafer shelves on each side are molded unitarily, that is a plurality ofshelves are molded as a single unit, a laterally inward recess isprovided by an end portion extending rearwardly from a generally arcuatesection that functions to maintain a maximum shelf width to facilitateinjection molding. This allows appropriate draft on the mold inserts(and molded piece) forming the shelves to allowing the inserts to beremoved during the molding process. In one embodiment, the recess isgenerally v-shaped. Thus in the plan view the front portion of theshelves has the shape of a checkmark providing easier molding.

In particular embodiments, the wafer shelf from the outer most seatingposition inwardly has a horizontal dimension, that is, width, of 14 to18 mm in the rearward lateral portions of the shelves,

Hereto before it is believed that sag during engagement by a endeffector, that is, a robotic hand that grasps a wafer for insertion andremoval, was not recognized as presenting similar interference issuesduring insertion and retrieval as the sag problem presented by wafersseated in a wafer container. The sag of the wafer when seated on the endeffector is at the lateral sides of the wafer, in the container portion,the sag of a wafer seated therein, without the door in place is at leastat the front and may be at the front and rear depending on the wafersupport arrangement at the rear of the container. Thus, optimizing thearcuate engagement regions of the end effector and the arcuateengagement regions of the container portion would be advantageous.Testing has surprisingly determined that wafer support at arcs extending90 degrees at only the lateral sides of a wafer provide essentially thesame sag resistance as 270 degrees of wafer support with only the frontopen. Thus, utilizing this concept in both the end effector and wafercontainer will provide optimally minimal sag during both engagements,the engagement with the end effector when the wafers are inserted andremoved, and the engagement with the wafer container, particularly whenthe door is not in place. Thus, the end effector will ideally grasp orengage the wafer at the front periphery and rear periphery at positionsdefining an arc that approaches 90 degrees. Similarly, the containerwill ideally support or engage the wafer contained therein, without thedoor on, at least approaching 90 degrees on each lateral side of thewafer. Clearances of between 2 mm and 10 mm are believed to beappropriate between the end effector's lateral margins and the wafersupports in the wafer container.

In a particular embodiment optimized to minimize sag both while thewafers are seated in the container portion and while the wafers arebeing transferred into or out of the wafer container, the wafer supportprovided by the container portion with the door removed and with thewafer seated in a position ready for robotic retrieval, the frontopening will be approximately 90 degrees, plus or minus 8 degrees. Inanother embodiment, 90 degrees, plus or minus 5 degrees, In a particularembodiment the rear availability for engagement of the wafer in a wafercontainer by an end effector will correspond with the front availabilityfor engagement with an end effector in said wafer container which willsubstantially match the angular access front opening. In an embodiment,the support provided at the front of the wafer by the end effector willapproach 90 degrees, for example about 84 to 88 degrees, the supportprovided at the rear peripheral edge of the wafer will approach 90degrees, for example about 84 to 88 degrees, the right and left lateralsupport provided by combs or shelves of the wafer container will eachapproach 90 degrees, for example about 84 to 88 degrees,

In a particular embodiment of a combination wafer container thatprovides peripheral wafer support and an end effector for insertion andremoval of wafers from the wafer container, each of the lateral wafersupports of the wafer container will extend more than 80 degrees, thefront access opening for receiving the end effector will be 85 to 100degrees, the end effector will be configured for engaging the rearperiphery of the wafer at positions defining an arc 80 to 95 degrees andfor engaging the front periphery of the wafer at positions defining anarc of 80 to 95 degrees. The container will allow access of the rearperiphery of the wafer by said end effector, that is the wafer peripherywilt be unsupported at the rear engagement positions of the endeffector.

In a particular embodiment of a combination wafer container thatprovides peripheral wafer support and an end effector for insertion andremoval of wafers from the wafer container, each of the lateral wafersupports of the wafer container will extend more than 85 degrees, thefront access opening for receiving the end effector will be 85 to 90degrees, the end effector will be configured for engaging the rearperiphery of the wafer at positions defining an arc 80 to 90 degrees andfor engaging the front periphery of the wafer at positions defining anarc of 80 to 90 degrees. The container will allow access of the rearperiphery of the wafer by said end effector, that is the wafer peripherywill be unsupported at the rear engagement positions of the endeffector.

In a particular embodiment of a wafer container, the arcuate range indegrees of available engagement of the rear periphery of a wafer in thewafer container by an end effector is within ten degrees of: the arcuaterange in degrees of available engagement of the front periphery of awafer; the arcuate continuous support of the lateral right periphery ofthe wafer in the wafer container, and the arcuate continuous support ofthe lateral left periphery of the wafer in the wafer container.

In an embodiment, the range of engagement of the end effector with therear peripheral edge of a wafer being withdrawn from a wafer containerwill be at least 80 degrees. In a particular embodiment, the range ofengagement of the end effector with the front peripheral edge of a waferbeing withdrawn from a wafer container will be at least 80 degrees.

With the wafer seated, the most rearwardly point of the wafer peripheryor edge is designated at zero degrees, the point of the wafer extendingmost laterally designated at 90 degrees, and the point of the wafer mostforwardly designated at 180 degrees, the wafer shelf in a preferredembodiment extends along the wafer on the sides of the wafers to aforward position of 115 to 130 degrees. This provides a front accessopening of 130 degrees to 100 degrees. In another embodiment a range of115 to 140 degrees providing a front access opening for the end effectorof 130 degrees to 80 degrees.

In particular embodiments, one or more deflectable wafer supports orwafer cushions also engage the wafers particularly when the wafers arein the second seating position. The wafer restraints are part of theinternal framework structure and are not positionally controlled by theshell, including deflection, movement, or expansion of the shell.

In certain embodiments, enhanced peripheral bottom surface support isprovided for the wafers that is believed to effectively eliminateexcessive sag of large 450 mm wafers. In such a case the peripheralunderside wafer support in the front opening container with the waferseated on the wafer supports without the door in position effectivelyextends around in an exaggerated C-shape approximately to 240°, about235° to 255° in certain embodiments, 235° to 265° in particularembodiments. In such embodiments, a second level of support when thedoor is in place may be provided by wafer restraints with V-shapedgrooves, either or both of rigid, non deflectable, or deflectable.Deflectable infers at least a 1.5 mm motion capability in normal use.Such deflection will typically be primarily in a horizontal directionduring normal use but may also have vertical components particularlywhen absorbing shock during transport.

The peripheral bottom surface support can be within 8 mm of the edge ofthe wafer in an embodiment, within 8 mm in another embodiment, andwithin 15 mm of the peripheral support in another embodiment, and within25 mm of the exterior edge in another embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a 450 mm wafer container in accord withaspects of the invention herein.

FIG. 2a is an exploded view of a wafer container in accord with aspectsof the invention herein.

FIG. 2b is an exploded view of a wafer container in accord with aspectsof the invention herein.

FIG. 3 is a rear perspective view of a shell for a wafer container inaccord with aspects of the invention herein.

FIG. 4 is a cut-away perspective view of a container portion in accordwith aspects of the invention herein.

FIG. 5 is a cut-away perspective view of a container portion in accordwith aspects of the invention herein.

FIG. 6 is a schematic view showing the extent of underside wafer supportin accord with aspects of the invention herein.

FIG. 7 is a detail cross-sectional exploded view showing an assemblyarrangement for the kinematic coupling plate, the shell and internalframework in accord with aspec

FIG. 8 is a detail exploded view of a shell, door frame, doorarrangement in accord with aspects of the invention herein.

FIG. 9 is a cross-sectional assembled view of the component portions ofFIG. 8 assembled and with the door engaged.

FIGS. 10 and 11 are schematic cross sectional views of wafer containerillustrating the cantilever support member defining a first level ofsupport and the forward and rearward wafer supports defining the secondlevel.

FIG. 12a is a perspective view of a 450 mm wafer container in accordwith aspects of the invention herein.

FIG. 12b is a perspective view of the container portion of the wafercontainer where the shell has been removed in accord with aspects of theinvention herein.

FIG. 13a is downward perspective view of a wafer shelf in accord withthe invention herein. The perspective view upwardly is a mirror image.

FIG. 13b is an opposite side downward perspective view of the wafershelf of FIG. 13a . The perspective view upwardly is a mirror image.

FIGS. 14 is a schematic cross-sectional view of wafer containerillustrating a V-shaped seating portion cross-section at a locationdirectly facing the insertion direction of the wafer in accord withaspects of the invention herein.

FIG. 15 is a schematic cross-sectional view of wafer containerillustrating a V-shaped seating portion cross-section at a location atthe side of the wafer container in accord with aspects of the inventionherein.

FIG. 16 is a partial cross-sectional view of a wafer container in accordwith aspects of the invention herein.

FIG. 17 is a perspective view showing the door of the wafer containerwhere the interior face is shown in accord with aspects of the inventionherein.

FIG. 18 is a partial close-up view of the front wafer constraintslocated on the interior of the door of the wafer container in accordwith aspects of the invention herein.

FIG. 19 is a perspective back side view of the wafer constraints of FIG.18.

FIG. 20 is a cross-sectional view of a unitary molded wafer support inaccord with aspects of the invention herein.

FIG. 21 is a graph displaying amount of wafer sag verses the angle ofthe opening for continuous wafer support with a single opening.

FIG. 22 is a perspective view of a jig utilized for collecting the dataof FIG. 21.

FIG. 23 is a graph displaying amount of wafer sag verses the angle ofthe opening for continuous wafer support with two opposed openings.

FIG. 24 is a perspective view of a jig utilized for collecting the dataof FIG. 23.

FIG. 25 is a view of an end effector and a wafer container portiondescribed herein with clearance regions per pending SEMI standard 4570A

FIG. 26 is a view of an end effector and a wafer container portion withclearance regions per pending SEMI standard 4570A and engagement arcsaccording to the invention herein.

DESCRIPTIONS OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring to FIGS. 1-12 b various views and embodiments of a wafercontainer 30 particularly suitable for large wafers, particularly 450 mmwafers, is illustrated. The wafer container generally comprises acontainer portion 40 and a door 42. The container portion generally hasa closed left side 43, a closed right side 44, a closed back 45, abottom side 46, a top side 47, and an open interior 48. The containerportion further comprises internal framework 50, a bottom machineinterface plate 54, a shell 58, a door frame 60, and wafer shelves 70. ASubstantially rectangular door frame 60 defines an open front. The door42 comprises latch mechanisms 80 with keyholes 82 and latching tips 84,a periphery 86, and an inside surface 88 with a wafer restraint 90thereon. The door latches are selectively engageable with the door frame60 of the container portion 40 and seal by way of an elastomeric seal94.

Referring to FIGS. 3, 4, 5, 7, 8, and 9, the shell 58 is preferablyformed of a polymer such as polycarbonate and may be attached to thedoor frame by sandwiching the lip 110 within the two pieces 1 14, 1 16of the door frame. A clamping may be effectuated by screws 118.Similarly, the shell may be sandwiched between the bottom machineinterface 54 and the internal framework 50 and secured by screws 118.The door frame 60 may be attached to the machine interface 54 by suchscrews or other means. The internal framework 50 may be comprised of aU-shaped top frame member 122, a U-shaped bottom base frame portion 124and a plurality of discrete attachment members 128 extending between thetop frame member 122 and bottom base frame portion for rigidly securingthe framework 50 together.

The wafer shelves, restraints, or combs 70 may be directly attached tothe framework 50 by way of posts 132 integral with the restraints, seeFIG. 4, or by other connection to the U-shaped pieces 122, 124, “Direct”attachment of two objects means the objects are held together inabutting relation by fasteners or other means. Door frame 60 may also bedirectly attached to the top from member 122 and/or the bottom baseframe portion 124. Wafer combs 70 are not directly attached to shell 58,only to the framework 50. Therefore, deflection, movement, or expansionof the shell 58 does not directly apply any force to wafer combs 70 andtherefore does not move or involve the wafers, so they will not bedamaged. The posts 132 may have threaded bores to allow screws to extendthrough holes in the U-shaped pieces 122, 124 for assembly to theframework 50. In one embodiment, the framework 50, bottom machineinterface plate 54, and door frame 60 may suitably be formed ofaluminum. The shell may be vacuum molded or injection molded. It may beunitarily formed or may be formed in different pieces and assembledtogether. Potential demarcation lines 135, 136, and 137 for convenientlymanufacturing separate shell pieces are dashed in FIG. 3.

Referring to FIGS. 4, 10, and 11, an embodiment may utilize wafersupports comprising cantilevered forwardly extending supports 138 thatare secured to the container portion at the back side of the containerportion. The cantilever supports are illustrated as dogleg shaped andare suitably placed to appropriately control sag of the wafers at aposition.

In certain embodiments, the positioning of the support provided by theforward extending cantilever support extends in at least 50 mm from theedge of the wafers. In other embodiments support extends at least 75 mm,100 mm, or 125 mm from the peripheral edge of the wafers. The cantileversupports may have contact pads thereon at the contact points, not shown.The wafers may be inserted into the container at a slot 140 to rest onthe cantilever supports defining a first level of support 150 and aseating position 151. At this level of support the wafer w may beexclusively supported by the cantilever supports or may be engaged forpositioning at the peripheral edge of the wafer. When the door isinserted the wafer is elevated by forward and rearward V-shaped waferrestraints 156, 158 to be raised to a second level of wafer support 162at a second seating position 164 where the cantilever wafer supports 138are not supporting the wafer. Note the second seating position 164 isabove and slightly rearward of the first seating position 151.

In the embodiment of FIG. 4, the wafer restraints comprise cantileversupports 138, rigid, non-deflectable V-shaped supports 158, and V-shapedcushions or deflectable restraints 162. The deflectable restraints 162conform to follow the edge of the wafer upon insertion and engagementwhen the wafer is at the second seating position. Although a singlewafer is illustrated in FIGS. 10 and 11, it should be understood thatthe entire vertically aligned array of wafers are moved and restrainedas described.

Referring to FIG. 5, an alternative peripheral support arrangement isillustrated that provides peripheral support on the underside surface ofthe wafer w either at the lower corner or within preferably 7 mm of thecorner, rather than support toward the middle of the wafer provided bythe cantilever support described above. The wafer restraints illustratedin FIG. 5 include rigid, non-deflectable supports 170, 172 that extendpast the forward-backward midpoint of the wafer, rigid non-deflectablesupports 174, 176 that are positioned at the back side of the containerportion, and deflectable wafer cushions 180, 182 positioned at the rearcorners of the container portion. The first and second wafer seatingpositions illustrated by FIGS. 10 and 1 1 and described by theassociated text, also apply to the FIG. 5 embodiment. Rather that thefirst seating position defined by supports off of the peripheral edge,that is, in the mid section of the bottom surface of the wafer, thefirst seating position is defined by the supports at the peripheraledge.

Referring to FIG. 6, it has been found that the peripheral support canprevent excessive sag of a 450 mm wafer w when the peripheral supportextends around defining a support arc 194, of about 240 degrees of thewafer periphery. In some embodiments, support extends about 235° to 255°and in certain embodiments, 230° to 265°, In a another embodiment, theopening between supports is between 85 and 110 degrees. This precludesexcessive sag and still allows maximum front side access to the wafers,such as be wafer end effectors for placement and removal of the wafers.

Referring to FIGS. 1 , 4, 8, 9 and 10, the unique configurationcomprising a interlaced door—door frame interface 300 is illustrated.The door frame 60 has an inwardly directed slot or groove 310 and thedoor has a projection or tongue 314 that enters the slot therebyconstraining said projection within the slot to provide an interlacingof structural features. The door frame 60 has an upper horizontalportion 320 and a lower horizontal 322 portion where the slot or slotsextend horizontally and are recessed inwardly with respect to thecontainer portion and the corresponding projection or projections on thedoor also extend horizontally and project rearwardly. When engaged insaid slot, the door 42 by way of the projections is constrained upwardlyand downwardly. Similarly the door frame may have a left verticalportion 336 and a right vertical portion 338 where the slot or slotsextend vertically and the corresponding projection or projections on thedoor also extend vertically and, when engaged in said slot or slots, thedoor is constrained to the left and to the right. The slot may becontinuous or not continuous around the door frame and similarly thedoor may have a single cooperating projection extending around theentire periphery of the door or more than one projection at selectedportions of the periphery of the door. In particular embodiments, theslot or groove will have an elastomeric seal 94 seated therein. In otherembodiments, a seal may be positioned out of the slot or groove or onthe door, see the region 352 of FIG. 9. Generally the seal will extendaround the entirety of the door frame defining the door opening andengage with the entirety of the door periphery. The seal may also extendaround the entirety of the door periphery and engage with the entiretyof the door frame defining the door opening.

FIGS. 12a and 12b provide an additional embodiment disclosing a wafercontainer 402 having a container portion 404 and a door 406 depictedwith outer shell removed for the sake of clarity. The exploded views ofFIGS. 2a and 2b relate to this embodiment. Within the container portion404 are right and left side wafer shelves 410 and 412 defining aplurality of V-shaped wafer slots 414, a back wafer restraint 420 withslots of V-shaped cross-section 424, and front wafer restraints 430 and432 on the interior face of door 406 having a flexible arrangement andslots 434 of V-shaped cross-section. Together the V-shaped slots and thesurrounding V-shaped portions of these components cooperate to positionand secure wafers of various sizes for transport and storage. These andvarious other aspects of this container can be understood from FIGS.14-20 as well. Detail of the shelves are shown in FIGS. 13a and 13 b.

In some embodiments, an inventive aspect may include variation in theangle of the V of the V-shaped engagement portions depending on thepositional placement of the V-shaped portions around the periphery ofthe wafer. In general, raising a wafer from a first shelf seatingposition (a wafer transfer position) to the second position (a transportposition), (similar to movement from position 151 to position 164 shownin FIGS. 10 and 11) where the door 406 is put in place and latched,occurs by the wafers moving in the z direction with respect to theV-shaped seating portions. See FIG. 14 for an indication of the zdirection with respect to the V-shaped slots on back and front waferrestraints 420, 430 and 432. Considering the larger 450 mm wafers, it isadvantageous to have several V-shaped seating portions that the wafercan ride up to reach the seating position at the apex of the Vs.

Where the V-shaped seating portion is directly facing the insertiondirection of the wafer (as on the back wafer restraint 420 for example),facing the z direction, the incline of the lower leg surface 510 is atthe most gradual slope and the angle a between the upper leg (downwardlyfacing) surface 512 and the lower leg (upwardly facing) surface 510 isat a minimum. See the V-shaped support cross-section in FIG. 14, forexample. Where V-shaped seating positions engage the wafer at a positionwhere the seating portion is facing more towards the JC axis, that is,more towards the sides of the container than the back of the container(as somewhere on side wafer shelf 412), the slope of the lower legsurface 510 will be greater and the angle β defined by the lower legsurface 520 and the upper leg surface 522 will be greater. See theV-shaped support cross-section in FIG. 15, for example. The component ofmovement perpendicular to the V-shaped wafer portion is much lesstowards the sides of the wafer container than at the back of the wafercontainer, thus the greater angle on the wafer engagement portionstowards the sides compared to the back side allows continual support atdifferent peripheral locations on the wafer edge as the wafer is beingelevated by the insertion of the door 406. This minimizes sag in thewafer. The V-shaped engagement portions may be isolated discreteportions extending a few millimeters horizontally to engage the wafer, 5to 20 mm in length, or can be much longer or even continuous on thebackside of each slot. In certain embodiments the lower leg surface(upwardly facing) of the engagement portions can have a curvature and,similarly, the curvature of the lower legs of the wafer engagementportions positioned nearer the sides will be steeper than the curvatureof engagement portion nearer the back side. The utilization of V-shapedengagement portions in elevating the wafer as the door is closed isdisclosed in U.S. Pat. No. 6,267,245.

The unique structures of the V-shaped groove components have a number ofadvantageous features as well. In various embodiments, a wafer engagingsurface 609 of lower leg 610 of the V-shaped groove may be longer than awafer engaging surface 611 of the upper leg 612 such that lower leg ofone wafer support extends beyond an extent of an upper leg of a wafersupport immediately below. This configuration is advantageous as itprovides a larger engagement region for larger wafers that may besagging. Such an arrangement can be seen in FIG. 16. This V-shapedgroove is suitable for placement on the inside backside of thecontainer, as at back wafer restraint 420, and also for placement at andsuitable for the front wafer restraints 430 and 432. Utilization ofwafer supports having various types of this fail-safe cross section arecontemplated as well. The length of lower leg 610 of the V-shaped groovecan be varied depending on the position of the V-shaped groove withrespect to a wafer seated in the container. This allows foraccommodation of sag during loading of the wafer and during theelevating of the wafer from a seating position without the door 406 inplace to a transport or door seated position. A horizontally extendinginverted ledge portion 614 having a downwardly facing ledge surface 613may connect each lower leg upwardly extending surface to the adjacentupper leg downwardly extending surface. This feature provides evengreater security and retention for storing wafers in this design.

FIGS. 17-19 depict one embodiment of front wafer restraints 430, 432according to the present invention. Wafer restraints 430, 432 areattached to an inside surface 407 of the door 406 and comprise aplurality of interconnected wafer supports 433 having V-shaped grooves434. V-shaped grooves 434 are defined by an upper leg 436 extendingupwardly and outwardly from door 406 and a lower leg 438 extendingdownwardly and outwardly from door 406. An apex 440 of each V-shapedgroove 434 is defined where upper legs 436 and lower legs 438 meet.Wafer restraints 430, 432 can angle inwardly into a recess 409 definedin door.

Wafer supports 433 also may have a first attached or base portion 460generally non-movably secured to the door 406 and a deflectable waferengagement portion 462 or enlarged pad that is the first portion tocontact the wafer when the door is applied to the container. Anintermediate portion 464 can connect the base portion 460 to thedeflectable wafer engagement portion 462. Intermediate portion 464 canhave an elongated aperture 470 at the apex of the V-shaped groove thatdefines fingers 472. The horizontal V may preferably extend the entirelyof length of the wafer restraint 432, Lower leg 480 of wafer engagementportion 462 can be larger than upper leg 482 due to apex of V-shapedgroove angling towards a top portion of upper leg from the aperture 470to an end portion of the wafer engagement portion 462. Adjacent wafersupports 433 are interconnected at respective base portions 460 whereasadjacent intermediate portions and wafer engagement portions are notinterconnected such that wafer engagement portion 462 and intermediateportion 464 are cantilevered from base portion 460.

Thus, in an aspect of the invention the wafer restraint has a baseportion 460, an intermediate dual finger portion 464 and a waferengagement pad portion 462 wherein the wafer engagement pad portion 462swoops or is angled downwardly thereby providing an enhanced engagementsurface for the wafer edge of sagging wafers. The dual fingers 472 atthe intermediate portion 464 provide torsional stiffness while allowingflexibility in the z direction compared to a single finger with the sameflexibility. In a preferred embodiment the lower leg 480 of the expandedpad will first contact the wafer edge as the door is being closed anddeflect as the wafer engagement point rides up the pad and into the apexof the V-shape.

Referring in particular to FIGS. 13a and 13b , arcuate lateral wafershelves 410 and 412 may simply be formed by a stack of individual shelfsections that are identical with adjacent shelves. Such an embodimentdoes not require formation of a single molded shelf section, which canbe difficult to make due to the challenging manufacturing shape of sucha molded component. The top of the piece may be a mirror image of thebottom allowing the same mold of a single shelf piece to make theentirety of the shelves on the left side and the shelves on the rightside. A series of apertures 483 may allow for rods to extend through thestacked shelf pieces for alignment and structural stability as well asattachment to the structural framework. The apertures 483 are typicallylocated at multiple locations around the perimeter of the individualshelf sections. An arcuate engagement area 485 extends substantially thelength of the component. Half of V-shaped support 487 is positioned onboth sides of the component

In preferred embodiments each shelf has a most forward end 675 thatfollows the periphery of the wafer and extends inwardly from thelaterally outermost edge of the wafer when seated a distance in therange of 50 to 60 mm. In another embodiment the distance is 55 to 65 mmand in another embodiment it is 52 to 56 mm. In certain embodiments, asshown in FIG. 20, where the wafer shelves 410 and 412 on each side aremolded unitarily, that is a plurality of shelves are molded as a singleunit, a support leg 678 can extend at an acute angle from the forwardend 675, thereby defining a laterally inward recess 680. Support leg 678functions to maintain a maximum shelf width with minimal expanses ofpolymer to facilitate injection molding. This allows appropriate drafton the mold inserts (and molded piece) forming the shelves to allow theinserts to be removed during the molding process. Moreover, thedecreased expanse of the polymer minimizes shrinkage and warpage issues.Thus in the plan view the front portion of the shelves has the shape ofa checkmark.

In some preferred embodiments the wafer shelf from the outer mostseating position inwardly typically has a horizontal dimension, that is,width, of 14 to 18 mm in the rearward lateral portions of the shelves.Also, once the wafer has seated, the general disposition of the waferand container arrangement may be described. When the most rearwardlypoint of the wafer periphery or edge is designated at zero degrees, thepoint of the wafer extending most laterally designated is at 90 degrees,and the point of the wafer most forwardly designated is at 180 degrees.According to this disposition and reference framework, the wafer shelfin a preferred embodiment extends along the wafer on the sides of thewafers a range of 115 to 130 degrees. In another embodiment, a range of115 to 140 degrees is used. Various other dispositions for wafer shelvesare possible as well.

Referring to FIGS. 21 to 24, a pair of jigs for testing the sag of 450mm wafers are illustrated and also test results using such jigs. It isbelieved, that it has not been recognized that sag during engagement byan end effector presents comparable interference issues during insertionand retrieval as the sag problem presented by a wafer container. Indeed,with 300 mm handling this was not a significant problem. Testing hasestablished significant sag when 450 mm wafers are handled byconventional end effectors and this sag can be eliminated by almost 50%whilst at the same time provided excellent sag prevention by the arcuatesupport in the wafer container.

The graph of FIG. 21 illustrates that with a continuous perimeter edgesupport and a single opening, a rapid increase 610 in the amount ofwafer sag occurs as the opening increases beyond about 90 degrees. Thus,considering the difficulties in molding or otherwise fabricating teeth,a front opening of about 90 degrees is indicated to be close to optimumcombination of molding and fabrication ease and benefit in sagprevention. FIGS. 23 and 24 presents the surprisingly results 611 thatwafer support at arcs extending 90 degrees at only the lateral sides ofa wafer provide essentially the same sag resistance as 270 degrees ofwafer support with only the front open. Thus, the need for continuous ornear continuous peripheral support around the entirety or near entiretyat the rear of the wafer to get maximum sag prevention has beensurprising disproved. Therefore, increasing the forward and rearwardengagement arcs of an end effector and the necessary elimination incontinuous or a reduced access area at the rear of the wafer results inan optimal combination of reducing sag during transfers by the endeffector and while the wafer is seated.

Thus, optimally the end effector forward and rearward engagement arcs,the wafer container lateral engagement arcs will all approach 90degrees. Necessary gaps for insertion and removal lower the maximum arcsto about 88 degrees. Thus, the end effector will ideally grasp or engagethe wafer at the front periphery and rear periphery at positionsdefining an arc that approaches 90 degrees. Similarly, the containerwill ideally support or engage the wafer contained therein, without thedoor on, at least approaching 90 degrees on each lateral side of thewafer.

FIG. 25 illustrates a proposed industry maximum limit sized end effector560 for engaging the 450 mm wafers W in a embodiment of a containerportion 562 described herein. FIG. 26 illustrates a combination endeffector with the increased size 570 indicated by the dashed lines incombination with a container portion 572. The engagement positions 576engage the wafer and define the engagement arcs.

The proposed industry standards has a permissible maximum engagement arc620 the periphery of the wafer of 68 degrees in the rear arcuateengagement area 621 of the wafer periphery and a maximum of 72 degreesin the front arcuate engagement area 622 for engaging the front arcuateengagement area of the wafer 623. The invention herein provides anincreased end effector engagement arc 630 approaching 90 degrees in therear arcuate engagement region 631 and a forward engagement arc 632approaching 90 degrees in the front 633. Moreover the side engagement ofthe wafer is preferable at least approaching 90 degrees on theengagement arc 636 on the right lateral side and the engagement arc 638on the right side for engaging the arcuate engagement areas 639 on thelater periphery of the wafer. Notably the wafer container may havesignificant wafer support regions rearward of the end effector positionsof engagement. That is the end effector contact with the wafer maysimply be at two points that define an arc approaching 90 degrees.“Approaching” a specific number of degrees means herein with 10 degrees,that is approaching 90 degrees means 80 to 90 degrees. “About” whenreferencing a particular number of degrees herein means within 5degrees.

“Connect” and “engage,” when used herein does not require directcomponent to component physical contact unless explicitly stated but mayinclude intermediate components that complete or contribute to theengagement or connection. The embodiments illustrated as holding a waferand the inventive aspects illustrated therewith should also beinterpreted as applying to other substrates such as flat panels.

The above disclosure is related to the detailed technical contents andinventive features thereof. People skilled in this field may proceedwith a variety of modifications and replacements based on thedisclosures and suggestions of the invention as described withoutdeparting from the characteristics thereof. Nevertheless, although suchmodifications and replacements are not fully disclosed in the abovedescriptions, they have substantially been covered by the spirit andtechnical theory of the subject invention.

The invention claimed is:
 1. A front opening wafer container forreceiving a plurality of wafers positioned in a stacked array with avertical axis, the container comprising: a container portion havingclosed lateral sides extending between a closed back and an open frontand defining an open interior; a plurality of interconnected wafersupports disposed within said container portion and extending fromproximate one of said closed lateral sides to proximate said closedback, said plurality of interconnected wafer supports defining aplurality of V-shaped grooves therebetween, each of said plurality ofV-shaped grooves defining a first apex, where each of the plurality ofinterconnected wafer supports meet for registration of a respective oneof a plurality of wafers therein, said first apex defining a first acuteapex angle; and a back wafer restraint disposed within said containerportion proximate said closed back, said back wafer restraint defining aplurality of V-shaped slots each defining a lower leg having anupward-facing engagement surface and an upper leg having adownward-facing engagement surface, each of said plurality of V-shapedslots defining a second apex where the lower leg and the upper leg ofeach of the plurality of V-shaped slots meet, the second apex insubstantial planar alignment with said first apex of a corresponding oneof said plurality of V-shaped grooves for registration of saidrespective one of said plurality of wafers, said second apex defining asecond acute apex angle, wherein said second acute apex angle is lessthan said first acute apex angle.
 2. The front opening wafer containerof claim 1, wherein said first acute apex angle varies continuouslyalong said V-shaped groove.
 3. The front opening wafer container ofclaim 1, wherein said first acute apex angle is greater proximate saidlateral side than proximate said closed back.
 4. The front opening wafercontainer of claim 3, wherein said first acute apex angle variescontinuously along said V-shaped groove.
 5. The front opening wafercontainer of claim 1, wherein for each of the plurality of V-shapedslots, said upward-facing engagement surface of said lower leg extendsfurther in a direction towards said open front than said downward-facingengagement surface of said upper leg.
 6. The front opening wafercontainer of claim 5, wherein, in said direction towards said openfront, said lower leg of a first V-shaped slot of said plurality ofV-shaped slots extends beyond said upper leg of a second V-shaped slotof said plurality of V-shaped slots, said second V-shaped slot beingadjacent and below said first V-shaped slot.
 7. The front opening wafercontainer of claim 1, comprising: a door attachable to said containerportion to close said open front; a wafer retainer disposed on an insidesurface of said door, said wafer retainer comprising a plurality ofvertically aligned horizontally-extending interconnected wafer supportsfor engagement of peripheral edges of a plurality of wafers as said dooris closes said open front, each of said plurality of wafer supportshaving a length and each including: a base portion non-movably attachedto said container; a deflectable initial wafer engagement portion; andan intermediate portion connecting said base portion and said waferengagement portion, said intermediate portion and said deflectableinitial wafer engagement portion cantilevered from said base portion. 8.The front opening wafer container of claim 7, wherein: adjacent wafersupports are interconnected to each other along respective base portionsand are not connected along respective intermediate portions or waferengagement portions; and when viewed in profile, an upper leg portionextends outwardly from said door and upwardly and a lower leg portionextends outwardly from said door and downwardly defining a generallyV-shaped portion with an apex including a V-shaped wafer engagementsurface with an apex, said upper leg portion and lower leg portionextending said length of said wafer support; and said intermediateportion having an elongated aperture therethrough providing a pair offingers extending horizontally intermediate said base portion and saiddeflectable wafer engagement portion.
 9. The front opening wafercontainer of claim 7, said door being selectively latchable to saidcontainer portion.
 10. A front opening wafer container for receiving aplurality of wafers positioned in a stacked array with a vertical axis,the container comprising: a container portion having closed lateralsides extending between a closed back and an open front and defining anopen interior; and a plurality of interconnected wafer supports disposedwithin said container portion and extending from proximate one of saidclosed lateral sides to proximate said closed back, said plurality ofinterconnected wafer supports defining a plurality of V-shaped groovestherebetween, each of said plurality of V-shaped grooves defining afirst apex, where each of the plurality of interconnected wafer supportsmeet, for registration of a respective one of a plurality of waferstherein, said first apex defining a first acute apex angle, a back waferrestraint disposed within said container portion proximate said closedback, said back wafer restraint defining a plurality of V-shaped slotseach defining a lower leg having an upward-facing engagement surface andan upper leg having a downward-facing engagement surface, each of saidplurality of V-shaped slots defining a second apex where the lower legand the upper leg of each of the plurality of V-shaped slots meet, thesecond apex in substantial planar alignment with said first apex of acorresponding one of said plurality of V-shaped grooves for registrationof said respective one of said plurality of wafers, said second apexdefining a second acute apex angle, wherein said first acute apex anglevaries depending on a positional location along said V-shaped groove,and said second acute apex angle is less than said first acute apexangle.
 11. The front opening wafer container of claim 10, wherein saidfirst acute apex angle varies continuously along said V-shaped groove.12. The front opening wafer container of claim 10, wherein said firstacute apex angle is greater proximate said lateral side than proximatesaid closed back.
 13. The front opening wafer container of claim 10,wherein for each of the plurality of V-shaped slots, said upward-facingengagement surface of said lower leg extend further in a directiontowards said open front than said downward-facing engagement surface ofsaid upper leg.
 14. The front opening wafer container of claim 13,wherein, in said direction towards said open front, said lower leg of afirst V-shaped slot of said plurality of V-shaped slots extends beyondsaid upper leg of a second V-shaped slot of said plurality of V-shapedslots, said second V-shaped slot being adjacent and below said firstV-shaped slot.
 15. A front opening wafer container for receiving aplurality of wafers positioned in a stacked array with a vertical axis,the container comprising: a container portion having closed lateralsides extending between a closed back and an open front and defining anopen interior; and a back wafer restraint disposed within said containerportion proximate said closed back, said back wafer restraint defining aplurality of V-shaped slots, each of said plurality of V-shaped slotsdefining an apex for registration of said respective one of saidplurality of wafers, said apex defining an acute apex angle, whereineach of said plurality of V-shaped slots defines a lower leg having aninclined upward-facing engagement surface and an upper leg having aninclined downward-facing engagement surface, said inclined upward-facingengagement surface of said lower leg extending further in a directiontowards said open front than said inclined downward-facing engagementsurface of said upper leg; and a plurality of interconnected wafersupports disposed within said container portion and extending fromproximate one of said closed lateral sides to proximate said closedback, said plurality of interconnected wafer supports defining aplurality of V-shaped grooves therebetween, each of said plurality ofV-shaped grooves for registration of a respective one of a plurality ofwafers therein and defining an apex having an acute apex angle, theacute apex angles of said plurality of V-shaped grooves being greaterthan the acute apex angles of said plurality of V-shaped slots.
 16. Thefront opening wafer container of claim 15, wherein said acute apex angleof the V-shaped grooves varies depending on a positional location alongsaid V-shaped groove.
 17. The front opening wafer container of claim 16,wherein said acute apex angle of the V-shaped grooves is greaterproximate said lateral side than proximate said closed back.